Humeral Implant and Method

ABSTRACT

A humeral implant is disclosed. The implant has a humeral surface component and a stem. The humeral surface component has an articular surface and is configured for fixation to an articular portion of a proximal humerus. The stem is configured for post-surgery axial movement within the humerus. The stem is connected to the humeral surface component opposite of the articular surface. A method of implanting a humeral implant is also disclosed.

FIELD OF THE INVENTION

The present invention relates in general to humeral implants.

BACKGROUND OF THE INVENTION

Orthopaedic surgeons often perform joint replacement surgery on patientswho suffer pain and physical limitations caused by joint surfaces whichhave degenerative, traumatic, or other pathologic damage. The success ofreplacement surgery is related to the degree of morbidity associatedwith the surgical technique and also to the ability of the surgery torestore the natural anatomy and biomechanics of the joint. The presentinventor recognized the need for improved rates of surgical successthrough an improved implant and method.

BRIEF SUMMARY OF THE INVENTION

A new humeral implant is disclosed. The implant has a humeral surfacecomponent and a stem. The humeral surface component has an articularsurface and is configured for fixation to an articular portion of aproximal humerus. The stem is configured for post-surgery axial movementwithin the humerus. The stem is connected to the humeral surfacecomponent opposite of the articular surface.

Accordingly, one aspect of the present invention is to provide a novelhumeral implant for shoulder replacement surgery that can be implementedwith conventional, minimally invasive, or novel surgical techniques.

Another aspect of the present invention is to provide a humeral implantwhich includes an articular surface component with anatomic geometrywith different radii of curvature in the axial and coronal planes.

Another aspect of the present invention is to provide a humeral implantwhich includes a stem that resides along a central axis of the proximalhumerus rather than in the intramedullary canal.

Another aspect of the present invention is to provide a humeral implantthat partially resurfaces the humeral head.

Another aspect of the present invention is to provide a humeral implantwhich obtains durable fixation on the subchondral bone of an anatomichead.

Another aspect of the present invention is to provide a humeral implantwhich obtains durable fixation with the non-articular lateral humeralcortex.

Another aspect of the present invention is to provide a humeral implantwhich obtains slidable engagement with a tunnel along a central axis ofthe humerus.

Another aspect of the present invention is to provide a humeral implantwhich obtains slidable engagement with the non-articular lateral humeralcortex.

Another aspect of the present invention is to provide a humeral implantwhich preserves humeral bone stock and allows increased physiologic loadtransmission from the joint surface in a patient's shoulder along thebone of the proximal humerus.

Another aspect of the present invention is to provide a humeral implantwhich has an interchangeable articular component and allows conversionbetween an anatomic shoulder arthroplasty and a reverse shoulderarthroplasty.

Another aspect of the present invention is to provide a modular bonereamer-which can be used with traditional open and transhumeralminimally invasive techniques for shoulder arthroplasty.

Another aspect of the present invention is to provide a modular bonereamer which can be used to prepare a humerus and a glenoid process in ashoulder joint without transecting their rotator cuff tendon and withoutdislocating their shoulder joint.

Another aspect of the present invention is to provide a modular bonereamer which can be used to prepare a humerus and a glenoid process in ashoulder joint perpendicularly to the shaft of the reamer.

A method of implanting a humeral implant is disclosed, comprising:fixing an articular humeral component comprising an articular surface toa prepared articular portion of a proximal humerus, placing a stem in atunnel in the proximal humerus without fixing the stem within the tunnelagainst post-surgery longitudinal movement; and, connecting the stem tothe articular humeral component.

Other features and advantages of this invention will be apparent toorthopaedic surgeons and other persons who are skilled in the art ofshoulder repair and reconstruction, particularly after reviewing thefollowing detailed description of the invention and the embodimentsthereof, from the claims, and from the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a perspective view of a portion of a humerus bone with acommon arthritic deformity of the humeral head.

FIG. 1B is a perspective view of a portion of a scapula bone with aglenoid process.

FIG. 2A is a side, partially transparent, view of a humeral implant ofthe invention utilizing a stem as described herein in position on aprepared humerus bone.

FIG. 2B is a side section view of a traditional humeral implantpositioned in a prepared humerus bone.

FIG. 2C is a side, partially transparent, view of another common humeralimplant utilizing fins in a metaphyseal position of a prepared humerusbone.

FIG. 3A is a top view of the articular humeral component of the humeralimplant of FIG. 2A disclosing the implant's elliptical shape whichincorporates varying radii of curvature.

FIG. 3B is a bottom view of the articular humeral component of thehumeral implant of FIG. 3A disclosing its bone ingrowth surface anddisposition of a coupling device for engaging an associated stem for theimplant.

FIG. 3C is a side view of a side of the articular humeral component ofthe humeral implant of FIG. 3A.

FIG. 3D is a side view of a first embodiment stem for the humeralimplant of FIG. 3A configured for fixed engagement of the implant withthe humeral bone.

FIG. 3E is a side view of a second embodiment stem for the humeralimplant of FIG. 3A configured for slidable engagement in the humeralbone.

FIG. 4 is a bottom view of a second embodiment of the articular humeralcomponent of a second embodiment humeral implant of the invention havingan offset coupling device for a stem.

FIG. 5 is side, partially transparent, view a third embodiment of a newhumeral implant of the invention having a partial articular componentshown in position on a prepared humerus bone.

FIG. 6A is a side view of a humeral implant of FIG. 3A with anassociated lateral buttress plate secured to the bone with screwsengaging the implant with a stem.

FIG. 6B is a second view of the humeral implant of FIG. 6A with anassociated lateral buttress plate secured to the bone with screws and/orscrews engaging the implant and the lateral buttress plate.

FIG. 7 is a side perspective view of a fourth embodiment humeral implantwith a concave articular portion for reverse shoulder arthroplasty.

FIG. 8 is a side perspective view the humeral implant of FIG. 7 with aconvex humeral articular component for anatomic shoulder arthroplasty.

FIG. 9A is an exploded side perspective view of the assembly of theconvertible humeral implant of FIG. 7 .

FIG. 9B is an exploded side perspective view of the assembly of theconvertible humeral implant of FIG. 8 .

FIG. 9C is a side perspective view of the shell of the convertiblehumeral implant of FIGS. 7 and 8 with a peripheral rim and fin(s) toresist subsidence and rotation respectively.

FIG. 10A is a perspective view of an ingrowth shell of the convertiblehumeral implant of FIG. 7 positioned in a prepared humerus bone with anassociated lateral buttress washer-plate secured to the bone with screwsengaging the implant with a stem.

FIG. 10B is a second perspective view of the ingrowth shell of FIG. 10A.

FIG. 11A is a perspective view of a handle arranged to hold the head ofa new humeral reamer.

FIG. 11B is a top view of the head of the new humeral reamer thatinteracts with the handle of FIG. 11A.

FIG. 11C is an elevational view of the head of the new humeral reamerthat interacts with the handle of FIG. 11A.

FIG. 11D is a bottom view of the head of the new humeral reamer and ofFIGS. 11B and C.

FIG. 11E is a side view of a portion of the shaft with engagement tip ofthe shaft and centering handle sleeve to interact with the head of thenew humeral reamer of FIGS. 11B, 11C, and 11D.

FIG. 12A is a side view of the humeral reamer and shaft preliminarilyarranged to be reversibly engaged to each other.

FIG. 12B is a side view of the humeral reamer and shaft of FIG. 12Areversibly engaged to each other.

FIG. 13A is a perspective view of the humeral reamer and shaft of FIG.12A arranged through a transhumeral passage in the humerus to prepare ahumerus for the installation of the new humeral implant.

FIG. 13B is a perspective view of the humeral reamer and shaft of FIG.13A arranged through a transhumeral passage in the humerus for a secondstep to prepare a humerus for the installation of the new humeralimplant.

FIG. 13C is a perspective view of the humeral reamer and shaft of 13Aarranged through a transhumeral passage in the humerus for a third stepto prepare a humerus for the installation of the new humeral implant.

FIG. 13D is a perspective view of the prepared humerus and transhumeralsheath after a fourth step to prepare the humerus for the installationof the new humeral implant where the reamer shaft and head of FIG. 13Aare disengaged and removed.

FIG. 14A is a side view of the humeral reamer and handle to prepare ahumerus for the installation of a new convertible humeral implant.

FIG. 14B is a bottom view of the humeral reamer of FIG. 14A.

FIG. 14C is a perspective view of the humeral reamer of FIG. 14A andshaft of FIG. 11E arranged through a transhumeral passage in the humerusfor a step to prepare a humerus for the installation of the newconvertible humeral implant.

FIG. 14D is a perspective view of the prepared humerus and transhumeralsheath after steps to prepare the humerus for the installation of thenew convertible humeral implant where the reamer shaft and head of FIG.14C are disengaged and removed.

FIG. 15A is an elevational view of the new modular glenoid reamer andhandle.

FIG. 15B is a second elevational view of the new modular glenoid reamerof FIG. 15A.

FIG. 15C is a side perspective view of a handle arranged to hold thehead of the new glenoid reamer of FIG. 15A.

FIG. 16A is a perspective view of the glenoid reamer of FIG. 15A andshaft of FIG. 11E arranged through a transhumeral passage in a humerusto prepare the glenoid for a glenoid implant.

FIG. 16B is a second perspective view of the glenoid reamer and shaft ofFIG. 16A arranged through a transhumeral passage in a humerus to preparethe glenoid for a glenoid implant.

FIG. 16C is a third perspective view of the humerus and glenoid of 16Aafter the glenoid and humerus have been prepared by humeral and glenoidreamers of FIGS. 13A and 16A through a transhumeral passage in thehumerus.

DETAILED DESCRIPTION OF THE INVENTION

Shoulder arthroplasty surgery traditionally requires transection of thesubscapularis tendon, dislocation of the shoulder joint and resection ofthe head 2 of the humerus bone 1 at the level of plane 6 of the anatomicneck (FIG. 1A) to gain sufficient access to prepare and resurface theglenoid 40 (FIG. 1B). Using a novel transhumeral method allows forproper access to the glenoid 40 while sparing the subscapularis tendonand avoiding dislocation and aggressive resection of humeral head bone2. Novel humeral implants 10, 13, 17 (FIGS. 2A, 5, 6A, 6B, 7, 8, 9A, 9B,10A, 10B) are usable with this novel transhumeral method, which providesa minimally invasive technique, but can also be used with traditionalsurgical techniques.

In the novel transhumeral method, the components of the new humeralimplants 10, 13, 17 can be inserted without cutting the rotator cuff nordislocating the shoulder joint through non-bony soft-tissue passagewayswith or without the assistance of transhumeral tunnel 7 to the shoulder.The novel humeral implants 10, 13,17 avoid the limitations associatedwith traditional humeral implants 35 having round, not oval shaped,articular components 36 with offset intramedullary canal stems 37designed to be fit in the intramedullary canal 38 of the humerus 1 (FIG.2B). Limitations associated with traditional humeral implants 35 includebut are not limited to aggressive humeral bone resection, complicatedimplant removal, and difficulty in obtaining anatomic parameters ofhumeral version, height, depth, inclination, and radius of curvature.

The novel humeral implant 10 also has improvements over other humeralimplants 39 fixed in the humeral metaphysis bone 5 (FIG. 2C). Thehumeral implant 39 has a round articular surfaces 36 a and intersectingelongated fins 39 a, 39 b extending from the component comprising thesurface 36 a. The novel humeral implant 10 is improved over implant 39,at least in that the novel implant utilizes the native dense articularsurface 3 and its subchondral bone 64 and non-articular lateral bonycortex 4 of the humerus for improved bony fixation and support of theimplant (FIG. 2A). The dense articular surface 3 comprises a thickness.Therefore, even when the humeral head bone 2 is prepared, such as shownin FIGS. 2A and 13D, to receive the novel implant at least a portion ofthe articular surface 3 is often retained after such preparation andthereby provides support for the implant.

The novel humeral implant 10 also allows for easier removal and bonepreservation during revision surgery. New humeral implants 13, 17 (FIGS.7, 8 ) also allow convertibility not afforded by prior art implants,such as implant 39. In some embodiments, the novel humeral implant 10has a smaller articular humeral component 26, having a smaller humeralarticulating surface 20 a, and only partially resurfaces the worn anddamaged humeral articular surface 3 (FIG. 5 ), as compared to thearticular humeral component 11 and articulating surface 20 of FIG. 2A.

The novel humeral implant 10 preserves the dense quality bone of theanatomic head 2 and comprises a removeably attached stem 12 a, 12 bwhich does not reside in nor rely on the intramedullary canal 38 forfixation (FIGS. 2A, 3D, 3E, 5 ). In some embodiment, the implant 10 ismodular at least in that the stem is connectable to the articularhumeral component 11. The implant 10 obtains stability from contact withgood quality bone from the anatomic head 2 and non-articular lateralbony cortex 4 of the humerus 1. The stem 12 a, 12 b is positioned in atranshumeral tunnel 7 along a central axis of the humeral metaphysis 5allowing for the use of articular humeral components 11, 26 each with asmooth articulating surface 20. In some embodiments, the articulatingsurface comprises variable more anatomic anterior-to-posterior andsuperior-to-inferior radii of curvature (FIGS. 3A, 3B, 3C, 3D, 3E, 4 ).

In some embodiments, the underside of the articular humeral components11, 26 has a bony ingrowth surface 21 and/or other bone adherentfeatures. In some embodiments, the articular humeral component 11 canalso have a central coupling site 22 or off-center coupling site 22 afor the stem 12 a, 12 b (FIGS. 3B and 4 ).

In some embodiments, the novel humeral implants 10, 13, 17 comprise astem 12 a, 12 b, 16 that provides slidable engagement with the bone ofthe humeral metaphysis 5 and/or non-articular lateral bony cortex 4 ofthe humerus 1 which allows for more physiologic loading of the humeralbone 1, 2, 3, 5 than with traditional humeral implants 35 and humeralimplants 39. Additionally, in the case of a periprosthetic humeralfracture complication, the design of the new humeral implants 10, 13, 17will provide for a pattern of proximal humeral fracture at the end ofthe unfixed stem, more easily managed than those predicted to occur withtraditional humeral implants 35 and humeral implants 39 and which doesnot compromise implant fixation.

The worn articular surface 3 of the humerus 1 can be prepared with amodular transhumeral reamer 50, 80 (FIGS. 11A, 11B, 11C, 11D, 11E, 12A,12B, 13A, 13B, 13C, 13D, 14A, 14B, 14C, 14D). The modular transhumeralreamer 50, 80 has a transhumeral reamer shaft 75 and modular cuttingreamer head 65, 81 with an attached handle 51 that still allows thereamer head 65, 81 to spin around its central axle 55 in the ring end 52while it is held in position by the handle 51. In one embodiment of thereamer 50, head 65 preserves a portion of the anatomic head 2, 64 of thehumerus to provide a sufficient bony support and fixation for thehumeral implant 10. In another embodiment of the reamer 80, the reamerhead 81 which reams into the vault of the humeral metaphysis 5 to allowfor new convertible humeral implants 13, 17 (FIGS. 14A, 14B, 14C, 14D).

Each convertible implant 13, 17 comprises an articular humeral component13 a, 17 a and a stem 16. The articular humeral component 13 a comprisesa shell 15 and an articular surface component 18. The articular surfacecomponent 18 comprises a convex articulating surface 20 and a couplingsurface 29. The articular humeral component 15 a comprises the shell 15and an articular surface component 14. The articular surface component14 comprises a concave articulating surface 25 and a coupling surface29. The stem 16 is the same as stem 12 a, 12 b, except that stem 16 mayhave a shorter longitudinal length as compared to stem 12 a, 12 b toaccount for the space occupied by the shell and portions of thearticular humeral component 13 a, 17 a.

Implants 13, 17 allow interchangeability of articular surface component14, 18 with either the convex or concave articulating surface 20, 25 toallow easy conversion between reverse shoulder arthroplasty and anatomicshoulder arthroplasty (FIGS. 7 and 8 ). The novel convertible humeralimplants 13, 17 each use the stem 16 and the shell 15 (9A, 9B, 9C). Thearticular surface components 14, 18 comprise coupling surfaces 27, 29that reversibly connect to the coupling surface 28 of the shell 15(FIGS. 7, 8, 9A, 9B, 9C). The coupling surfaces 27, 29 of the articularportions 14, 18 may possess variable geometry and one of a variety ofreversible coupling mechanisms, such as threads. The articular portions14, 18 may be modular and possess structural voids to reduce weight. Theshell 15 may comprise variable protruding geometry with a bony ingrowthsurface 21, a peripheral rim 19 to rest upon the prepared cortical rim 9of the proximal humerus and fins or other prominences 45 extending fromthe protruding side of the shell 15 (FIGS. 7, 8, 9A, 9B, 9C, 10A, 14D).

The stem 12 a, 12 b, 16 is positioned to reside in the transhumeraltunnel 7 along a central axis of the humeral metaphysis 5 transverse tothe plane 6 of the humeral anatomic neck, such as shown in FIGS. 2A, 5and 7 . In some embodiments, the stem 12 a, 12 b, 16 and thetranshumeral tunnel 7 are perpendicular to the plane 6 of the humeralanatomic neck. The stem 12 a, 12 b, 16 can possess a first end 23 with acoupling feature 23 a to engage the opposite coupling feature 22, 22 aof the humeral implants 10, 13, 17. In some embodiments, the couplingfeatures 22, 22 a, 23 a, comprise threads, a press fit, or a morsetaper, or other suitable coupling mechanism to join the stem to thearticular component 11, 13 a, 17 a, 26. It is possible for the male orfemale counterpart to be on either the stem 12 a, 12 b, 16 or thearticular component 11, 13 a, 17 a, 26 with the opposite counterpart onthe other of the stem 12 a, 12 b, 16 or the articular component 11, 13a, 17 a. In some embodiments, in the case of the coupling feature 22comprising threads, the coupling feature 22 is a receiver having aperipheral wall surrounding an opening for receiving the stem 12 a, 12b, 16, the peripheral wall comprises interior threads for engaging thethreads at the first end 23 of the stem. In some embodiments, the stem12 a, 16 comprises a second coupling feature, such as threads or apress-fit, at a second end 24 of the stem opposite the first end asshown for stem 12 a in FIG. 3D (not shown for stem 16).

In some embodiments, the second end of the stem 12 b, 16 does notcomprise a second coupling feature but instead may be smooth, such asshown in FIGS. 3E and 9A. The second end of the stem 12 a, 12 b, 16,whether comprising a second coupling feature or not, obtains contact andstability against the bone of non-articular lateral bony cortex 4 and/orthe bone of the humeral metaphysis 5 (FIGS. 2A, 5, 7, 8 ), whenimplanted. In various embodiments, the stem may comprise differentlengths. In some embodiments, the stem comprises a length such that thestem engages only the bone of the metaphysis 5. In some embodiments, thestem comprises a length such that the stem extends beyond the metaphysis5 to also engage the non-articular lateral bony cortex 4, and the stemmay or may not extend past the lateral end of the lateral bony cortex 4.Therefore, the stem can be contained within the transhumeral tunnel ormay extend out of the transhumeral tunnel at the lateral end of thelateral bony cortex 4. In some embodiments, the stem 12 a, 12 bcomprises a length in the range of 1 centimeter (cm) and 12 cm,inclusive. In some embodiments, the stem 16 comprises a length in therange of 1 cm and 6 cm, inclusive. In some embodiments, the stem 12 a,12 b, 16 comprises a length that is configured to engage sufficientstructural bone of the humerus to resist non-longitudinal displacementof the stem.

In some embodiments and applications, the stem 12 a, 12 b, 16 alsoengages a coupling site 31 of the washer-plate 30 on the non-articularlateral bony cortex 4 of the humerus to improve implant stability (FIGS.6A, 6B, 10A, 10B). In some embodiments, the coupling site 31 comprisesthreads on a wall of the aperture where the stem is received. Therefore,when the second end 24 of the stem comprise threads, the thread the stemengage the thread of the coupling site 31.

In some embodiment and applications, the stems 12 a, 12 b, 16 areconfigured for slidable engagement with the non-articular lateral bonycortex 4 of the humerus, the washer-plate 30, and/or the bone of thehumeral metaphysis 5 to allow more physiologic load transmission ofjoint compressive forces to the remainder of the bone of the humerus 1through the humeral implants 10, 13, 17. The stem 12 a, 12 b 16 isconfigured not to be axially fixed within the transhumeral tunnel, butinstead to slide within the transhumeral tunnel 7, including afterimplantation surgery is complete, i.e. post-surgery. The stem can slidelongitudinally within the transhumeral tunnel 7 and axially along alongitudinal axis 12 c, 16 a of the stem, in the directions A and B ofFIG. 2A and directions C and D of FIG. 7 . The stem 12 a, 12 b 16 can belimited in its sliding range of motion in the first direction B, D, atthe first end 23 by the articular component 11, 13 a, 17 a engagementwith the humeral head. The stem does not axially shelter the load bornby the articular component from the surrounding proximal humeral bone indirection B, D. This non-load-sheltering aspect of the stem contributesto more physiologic load transmission of joint compressive forces to theremainder of the bone of the humerus 1 through the humeral implants 10,13, 17. In some embodiments, the width or diameter of the stem 12 a, 12b, 16 less than the width or diameter of the transhumeral tunnel 7 andtherefore stem does not friction fit against the wall(s) of thetranshumeral tunnel 7 and therefore the stem is slidable within thetranshumeral tunnel 7, including post-surgery. In some embodiments, thestem 12 a, 12 b, 16 can be provided with a smooth exterior, such as asmooth exterior surface below the coupling feature 23 a at the first end23 of the stems shown in FIGS. 3E and 9A. And, at least the second end24 may be smooth, such as shown in FIGS. 3E and 9A. In some embodiments,the stem has a uniform width and cross-section along the longitudinallength of the stem or a portion thereof.

In some embodiments, the second end 24 of the stem 12 a, 12 b, 16 isenlarged to prevent movement toward the articular component in thedirection A, C, where the enlarged portion engages with a portion of thetunnel 7, which is narrower than the enlarged portion, at least in part,to prevent further movement in the direction A, C. In some embodiments,the stem 12 a, 12 b, 16 comprises ridges, fins, and/or unidirectionalridges and these features of the stem do not limit movement of the stemaway from the articular component along its axis, such as in thedirection B, D. In some embodiments, the stem 12 a, 12 b, 16 may beconsidered nonadherent within the tunnel 7 in that they allow movementaway from the articular component, such as in the direction B, D. Therange of movement in a first direction of the stem within the tunnel maybe limited by the articular components' engagement with the preparedportion of a proximal humerus via the connection between the stem andthe articular components. In some embodiments, the range of movement ofthe stem in a second direction, opposite the first direction, in thetunnel 7 may be limited by an enlarged second end 24 of the stem and itsengagement with the tunnel or another fixture.

In some embodiments, the washer-plate 30 does not have a coupling siteand instead a nut (not shown) is fixed to the threaded second end 24 ofthe stem 12 a, 12 b, 16 after the plate (e.g. to the left of the platein FIG. 6A). In such embodiments, the stem, by not being fixed to theplate, the non-articular lateral bony cortex 4, or the perimeter of thetranshumeral tunnel 7, the stem is allowed movement along the axis ofthe stem within a range bounded by the nut. The nut limits the range ofmovement, in the second direction, away from the non-articular lateralbony cortex 4 and toward articular humeral component 11 or shell 15, butnot towards the non-articular lateral bony cortex 4.

Alternatively, the stems 12 a, 12 b, 16 can capture either thenon-articular lateral bony cortex 4 of the humerus or an optionalwasher-plate 30 and the articular humeral component 11 or the shell 15of the humeral implants 10, 13, 17, serving to compress them togetheragainst the intervening elements of humeral bone 3, 4, 5 (FIGS. 3D, 6A,6B, 10A, 10B). In some embodiments, screws 33 can be used throughcannulations 32 to help secure the washer-plate 30 to the non-articularlateral bony cortex 4 of the humerus (FIGS. 6A, 10A). The screws 33 canbe used to compress the washer-plate 30 against lateral bony cortex 4 ofthe humerus 1 or can be fixed angle and locking to achieve rigidfixation to the humerus bone 1. Additional screws 33 can also bridgebetween cannulations 32 in the washer-plate 30 and screw optionalcoupling sites 34 of the humeral implants 10,13,17.

The portions of the shell 15 and the articular humeral components 11, 26that interface with the bone may have a suitable protruding bonyingrowth surface(s) 21 to allow long-lasting adhesion to the humeralhead 2 and metaphysis bone 5. Each stem 12 a, 12 b, 16 has two ends 23,24 (FIGS. 3D and 3E). One end 23 removeably attaches to the couplingdevice 22 of the shell 15 or the articular humeral components 11, 26 andanother end 24 which engages the non-articular lateral bony cortex 4 ofthe humerus or the coupling site 31 of an optional washer-plate 30 fixedto the non-articular lateral bony cortex 4 of the humerus, or a nut, asexplained above. In some embodiments, the remainder of the stem 12 a, 12b, 16 may possess a bone ingrowth surface but ideally would not tofacilitate slidable engagement and removal as necessary. Alternatively,the end 24 of the stem 12 a, 12 b,16 may be smooth and allow slidablecontact with the lateral washer-plate 30, the non-articular lateral bonycortex 4 and/or transhumeral tunnel 7 along a central axis in themetaphysis 5 of the humerus 1, as more fully explained above.

In some embodiments, modular transhumeral reamers 50, 80, 90 areutilized to prepare the humeral and glenoid surfaces 3, 42 for novelimplant application (FIGS. 12A, 14A, 15A). Reamer 50, 80, 90 comprises acutting reamer head 65, 81, 91 with an axle 55, a central cannulation56, 93, and a handle 51 (FIGS. 11A, 11B, 11C, 11D, 11E, 14A, 14B, 15A,15, 15B, 15C). The handle 51 has a ring end 52 which captures the axle55 and allows the axle 55 and the reamer head 65, 81, 91 to spin freelyin the ring end 52. The reamer head 65, 81, 91 has a surface configuredfor bone drilling or cutting 66, 67, 83, 92, 96 and a slot 57, 98,opposite the cutting or drilling surface configured for temporaryengagement with the tip 76 of the transhumeral reamer shaft 75. Theshaft 75 of the reamers 50, 80, 90 can be driven by hand or a powerdrill 77.

The reamers 50, 80, 90 are modular and may be used through open surgicalapproaches used for traditional open shoulder arthroplasty surgery orthey can be used for minimally invasive rotator cuff sparing shoulderarthroplasty surgery through a transhumeral tunnel 7 approach whichspares the rotator cuff, preserves humeral bone, and avoids dislocationof the shoulder joint associated with traditional approaches. For thetranshumeral approach, the reamers 50, 80, 90 are inserted by theirhandle 51 through a non-bony passageway, likely an interval in therotator cuff, and into position in the shoulder joint while thetranshumeral reamer shaft 75 is inserted through the transhumeral tunnel7 and an optional protective transhumeral sheath 8 into the shoulderjoint and reversibly coupled by the engagement tip 76 to the engagementslots 57, 98 of the reamer 50, 80, 90 (FIGS. 13A, 13 B, 13C, 13D, 14C,14D, 16A, 16B, 16C). The reamer 50, 80, 90 can be configured to be usedto drill and cut transverse or perpendicular to the axis of the reamershaft 75, particularly not off-axis. For example, the cut surfaces 65 a,b, c, of the prepared portion of humeral head shown in FIG. 13D afterthe use of the reamer in FIGS. 13B and 13C shows that the reamer can cutplanes that are perpendicular to the axis of the reamer shaft 75. Thereis a centering sleeve 78 moving freely around the reamer shaft 75 thatengages a centering cannulation 58, 82 on the reamer heads 65, 81 toensure the reamer cuts the humeral surface 3 on axis, i.e perpendicularto the transhumeral tunnel 7 and the reamer shaft 75. The glenoid reamer90 does not require a centering sleeve 78 but rather is cannulated 93 toream over a guide pin 100 positioned through the transhumeral tunnel 7and the protective transhumeral sheath 8 and into the surface 42 andvault 41 of the glenoid 40 (FIGS. 16A, 16B, 16C). The reamer shaft forthe glenoid also possesses a cannulation 74 for the guide pin 100.

The cutting surfaces 66, 67, 83, 84, 92, and 96 vary in geometry andaggressiveness to optimally prepare the bone 3, 5, 41, 42 for theirrespective implants 10, 13, 17. The reamer head 65 has two cuttingsurfaces 66, 67, one cutting surface 66 to cut the humeral surface 3 andthe other cutting surface 67 to cut the perimeter to the level 6 of theanatomic neck of the humerus 1 (FIG. 11D). The reamer head 81 for theconvertible humeral implant 13,17 also has two cutting surfaces, oneprotruding cutting surface 83 with variable geometry to cut a humeralmetaphyseal socket 85 and a second 84 to cut the perimeter near thelevel 6 of the anatomic neck of the humerus 1(FIGS. 14A, 14B). Thecutting surface 92, 96 of the glenoid reamer 90 has a protrudingaggressive cutting surface 92 to cut a precise glenoid cavity 44 intothe glenoid vault 41; an intermediate smooth non-cutting surface 94 tohelp keep the reamer 90 on axis and prevent damage to preparedperipheral glenoid surface bone 43; and a less aggressive cuttingsurface 96 on the peripheral rim 95 of the glenoid reamer head 91 toless aggressively prepare the peripheral aspect of the glenoid surface42 (FIGS. 16A, 16B, 16C).

In some embodiments, the implants 10, 13, 17 can be implanted through animplant method that comprises the following steps: fixing an articularhumeral component 11, 26, 13 a, 17 a comprising an articular surface 20,25 to a prepared articular portion of a proximal humerus; placing a stem12 a, 12 b, 16 in the tunnel 7 in the proximal humerus without fixingthe stem within the tunnel 7; and, connecting the stem to the articularhumeral component. Depending on the chosen approach for implantation,the order of the foregoing steps can vary. Further, in some embodiments,the connecting step is not used, for example, when the stem is alreadyfixed to or formed with the articular humeral component.

In some embodiments, the step of connecting occurs before the articularhumeral component is fixed to the proximal humerus, and in some cases,before the stem is placed in the tunnel 7. For example, when the stemand the articular humeral component are implanted as a unit, the stembeing placed from the articular side of the humerus into the tunnel 7toward the lateral bony cortex 4, in the direction D, B. The stem beingmoved into the tunnel until the articular humeral component is seated onthe prepared articular portion. The articular humeral component may befixed at or after the humeral component is seated on the preparedarticular portion.

In some embodiments, the stem is placed through tunnel 7 from thelateral bony cortex 4 side in the direction A, C and is connected to thearticular humeral component before the articular humeral component isfixed to the prepared articular portion of a proximal humerus. In someembodiments, the stem is placed in the tunnel, the articular humeralcomponent is fixed to the prepared articular portion of a proximalhumerus, and then the stem is connected to the articular humeralcomponent.

In some embodiments, the step of connecting occurs during the step ofplacing. For example, the stem may be connected articular humeralcomponent when it is placed within the tunnel. As explained above, insome embodiments, the stem is placed in the tunnel 7 in the proximalhumerus without fixing the stem within the tunnel against post-surgerylongitudinal movement.

It is therefore intended that the foregoing detailed description beregarded as illustrative rather than limiting, and that it be understoodthat it is the following claims, including all equivalents, that areintended to define the spirit and scope of this invention.

1. A humeral implant comprising: an articular humeral componentcomprising an articular surface and configured for fixation to anarticular portion of a proximal humerus; and a stem configured forpost-surgery axial movement within the humerus, the stem is connected tothe articular humeral component opposite of the articular surface. 2.The humeral implant of claim 1, wherein the stem comprises anon-bone-adherent surface.
 3. The humeral implant of claim 1, whereinthe stem comprises a non-bone-adherent coating on an exterior surface ofthe stem.
 4. The humeral implant of claim 1, wherein the stem comprisesa length sufficient to traverse a non-articular lateral bony cortex ofthe humerus opposite the articular portion.
 5. The humeral implant ofclaim 1, wherein the articular humeral component comprises a bonefixation component and an articular surface component, the stem isremovably connected to the bone fixation component, the bone fixationportion is removably connected to the articular surface component, thearticular surface component comprises the articular surface.
 6. Thehumeral implant of claim 1, wherein the stem comprises a cylindricalshape.
 7. The humeral implant of claim 1, wherein the stem is axiallynon-load-sheltering.
 8. The humeral implant of claim 1, wherein the stemis removably connected to the articular humeral component.
 9. Thehumeral implant of claim 1, wherein the stem is permanently connected tothe articular humeral component.
 10. The humeral implant of claim 1,wherein the articular humeral component comprises a bone fixationcomponent, and the bone fixation component comprises a cannulation. 11.The humeral implant of claim 10, comprising a screw within thecannulation.
 12. The humeral implant of claim 1, comprising a washerplate for engaging a lateral non-articular bone surface of the humerus,the washer plate configured to receive the stem.
 13. The humeral implantof claim 12, wherein the stem is axially slidably received by the washerplate.
 14. The humeral implant of claim 1, wherein the stem extendsalong a central axis of a neck of the humerus.
 15. A method ofimplanting a humeral implant, comprising: fixing an articular humeralcomponent comprising an articular surface to a prepared portion of aproximal humerus; placing a stem in a tunnel in the proximal humeruswithout fixing the stem within the tunnel; and, connecting the stem tothe articular humeral component.
 16. The method of claim 15, wherein thestep of placing is further defined in that the stem is not frictionfitted within the tunnel.
 17. The method of claim 15, wherein the stepof placing is further defined in that the stem comprises a length thatis shorter than a length of the tunnel to allow the stem to movelongitudinally within the tunnel.
 18. The method of claim 15, whereinthe step of placing is further defined in that the stem comprises alength sufficient to traverse a non-articular lateral bony cortex of thehumerus opposite the articular surface to allow the stem to movelongitudinally within the tunnel.
 19. (canceled)
 20. (canceled) 21.(canceled)
 22. (canceled)
 23. (canceled)
 24. (canceled)
 25. (canceled)26. A humeral implant comprising: an articular humeral componentcomprising an articular surface and configured for fixation to anarticular portion of a proximal humerus; and an axiallynon-load-sheltering stem connected to the articular humeral componentopposite of the articular surface.
 27. A method of implanting a humeralimplant, comprising: placing a stem in a tunnel in a proximal humeruswithout fixing the stem within the tunnel; and, fixing an articularhumeral component, that is connected to the stem and comprises anarticular surface, to a prepared portion of the proximal humerus. 28.(canceled)
 29. (canceled)
 30. (canceled)
 31. (canceled)
 32. (canceled)33. (canceled)